1. Field of the Invention
The present invention relates in general to a trolley wheel, and more specifically, to an improved trolley wheel having superior wear characteristics.
2. Description of the Prior Art
Animal carcasses are transported in meat packing plants typically through the use of meat hooks. Each meat hook is secured to a wheel by a strap or other connection means to form a trolley. The trolleys move along a track system to transport the carcasses from place to place. Each trolley typically includes a wheel having a recessed rolling surface which rides along the track system and a pair of perimeter flanges to prevent the wheel from "jumping the track." A typical meat packing operation may employ hundreds or thousands of such trolleys.
Prior art trolley wheels are typically constructed of iron, or a similarly soft material, so as not to cause excessive wear on the track system. The wheels are typically provided with a brass or other type of bushing to allow the wheels to turn upon an axle. While the iron construction of the wheel does reduce the amount of wear on the track, iron tends to rust. Over time, however, this rust begins to flake off the wheel. If rust flakes fall off the wheel and onto the animal carcass hanging below, contamination is a significant concern.
An additional drawback associated with prior art wheels is the difficulty in cleaning such wheels. To clean the wheels and remove rust flakes, the entire trolley is typically washed in hot caustic. The caustic aids in removing rust flakes, while the temperature of the caustic, typically one hundred and eighty degrees, kills bacteria on the wheel. The heat also serves to aid in the drying of the trolley when the trolley exits the caustic.
A light coating of oil is applied to prior art trolleys to reduce oxidation and rust. After the trolleys exit the hot caustic, the oil cannot be applied until the trolley is dry. Although the heat of the trolley exiting the caustic aids in drying the trolley very quickly, the freshly cleaned metal is exposed to the atmosphere for a short time before the oil is applied. During this short period of time, oxygen in the atmosphere oxidizes the trolley to form a thin coat of rust over the trolley. While most of this rust is removed during the next cleaning cycle, the constant rusting and rust removal subjects the trolley to premature wear.
Still another downside associated with the prior art is the likelihood of contamination as the light coating of oil slides down the trolley and drips down to contaminate the animal carcass. Still another drawback associated with the prior art is the short life span of the trolley wheel. The trolley wheel is constructed of iron, is continuously moved over a steel or otherwise hard surface, and is constantly worn down. The typical life span of a trolley wheel is, therefore, short, averaging a year or less depending upon the amount and severity of use.
The drawbacks associated with the prior art noted hereinabove are substantially eliminated by the present invention.